Battery pack containing phase change material

ABSTRACT

A battery pack for a vehicle including a first module group comprising at least one battery module; a second module group comprising at least one other battery module; and a manually operable interrupter assembly selectively electrically connecting the first module group to the second module group in series, the interrupter assembly being adapted for opening and closing a circuit connecting the first and second module groups.

CROSS-REFERENCE

The present application is a divisional application of U.S. patentapplication Ser. No. 16/158,410, filed Oct. 12, 2018. U.S. patentapplication Ser. No. 16/158,410 is a divisional application of U.S.patent application Ser. No. 15/546,232, filed Jul. 25, 2017, whichissued as U.S. Pat. No. 10,128,550, on Nov. 13, 2018. U.S. patentapplication Ser. No. 15/546,232 is a national stage entry ofInternational Application No. PCT/M2016/050511, filed Feb. 1, 2016,which claims priority to United States Provisional Patent ApplicationNo. 62/109,970, filed Jan. 30, 2015. The entirety of each application isincorporated herein by reference.

FIELD OF TECHNOLOGY

The present technology relates to rechargeable battery packs for use invehicles.

BACKGROUND

It is known to use phase-change materials (PCM) for thermal managementof battery packs. For example, U.S. Pat. No. 6,468,689 (Al-Hallaj etal.), U.S. Pat. No. 6,942,944 (Al-Hallaj et al.) and U.S. Pat. No.8,273,474 (Al-Hallaj et al.), all issued to Allcell, each disclose a PCMcomprising a paraffin wax for use in a pack comprising rechargeablebattery cells. Each of these patents is incorporated herein byreference.

An example of such a PCM material is the Phase Change Composite (PCC™)thermal management material from AllCell Technologies LLC.

SUMMARY

It is an object of the present technology to improve currentrechargeable battery packs, in particular for use in vehicles such asmotorcycles, all-terrain-vehicles, snowmobiles, personal watercraft andthe like.

In one aspect, implementations of the present technology provide abattery pack including a plurality of modules connected in series, eachmodule having a nominal voltage of between 18 Vdc and 32 Vdc, theplurality of modules having a combined nominal voltage of between 84 Vdcand 112 Vdc, each module comprising between six and 20 bricks connectedin series, each brick including between ten and 60 electrochemical cellsconnected in parallel; and a phase change material for dissipating atleast a portion of heat generated upon activation of at least a portionof the electrochemical cells, the phase change material at least in partenveloping the electrochemical cells.

In another aspect, implementations of the present technology provide abattery pack including:

a plurality of electrochemical cells having a T_(max-charge) and a phasechange material for dissipating at least a portion of heat generatedupon activation of at least a portion of the electrochemical cells, thephase change material at least in part enveloping the electrochemicalcells, the phase change material having a T_(melt)<T_(max-charge).

In another aspect, implementations of the present technology provide abattery pack comprising a plurality of bricks connected in series, eachbrick including:

a plurality of electrochemical cells, and

a phase change material for dissipating at least a portion of heatgenerated upon activation of at least a portion of the electrochemicalcells, the phase change material at least in part enveloping theelectrochemical cells, the plurality of electrochemical cells beingdisposed in an alternating pattern within the phase change material,

wherein the alternating pattern enables the formation of channelsbetween at least some of the electrochemical cells, and

wherein the battery pack further comprises connectors for conductivelyconnecting adjacent bricks, the connectors being disposed within thechannels.

In another aspect, implementations of the present technology provide abattery pack including:

a plurality of electrochemical cells,

a phase change material for dissipating at least a portion of heatgenerated upon activation of at least a portion of the electrochemicalcells, the phase change material at least in part enveloping theelectrochemical cells,

a housing for containing the plurality of electrochemical cells and thephase change material, the housing made of a metallic material, and

a layer of thermally conductive adhesive between the at least a part ofthe phase change material and the housing.

According to another aspect of the present technology, there is provideda battery brick for a vehicle, comprising a phase change material havinga melting temperature; and a plurality of battery cells, each batterycell of the plurality of battery cells being disposed at least in partin the phase change material, the plurality of battery cells having amaximum charge temperature and a maximum discharge temperature, themaximum charge temperature of the battery cells being less than themaximum discharge temperature, the phase change material being adaptedfor dissipating at least a portion of heat generated upon activation ofat least a portion of the plurality of battery cells, the meltingtemperature of the phase change material being less than the maximumcharge temperature of the plurality of battery cells.

According to another aspect of the present technology, there is provideda battery pack for a vehicle, comprising a plurality of battery modulesconnected to one another, each of the plurality of battery modulescomprising a plurality of the battery bricks.

In some implementations of the present technology, the plurality ofbattery modules are connected to one another in series.

In some implementations of the present technology, the plurality ofbattery bricks are connected to one another in parallel.

According to yet another aspect of the present technology, there isprovided a battery pack for a vehicle, comprising a plurality of bricks,each brick of the plurality of bricks comprising a phase change materialblock, a side of the phase change material block defining a plurality ofchannels, and a plurality of battery cells, each battery cell beingdisposed at least in part in the phase change material block; and atleast one connector for electrically connecting a first one of theplurality of bricks to a second one of the plurality of bricks, the atleast one connector being disposed at least partially in one of theplurality of channels.

In some implementations of the present technology, the first one of theplurality of bricks is adjacent to the second one of the plurality ofbricks.

In some implementations of the present technology, the plurality ofbricks are electrically connected to one another in series.

In some implementations of the present technology, the side of the phasechange material block is a top side of the phase change material block.

In some implementations of the present technology, the first one of theplurality of bricks further comprises a positive current collectorelectrically connected to the plurality of battery cells of the firstone of the plurality of bricks; the second one of the plurality ofbricks further comprises a negative current collector electricallyconnected to the plurality of battery cells of the second one of theplurality of bricks; and the at least one connector electricallyconnects the positive current collector of the first one of theplurality of bricks to the negative current collector of the second oneof the plurality of bricks.

In some implementations of the present technology, the battery packfurther comprises at least one insulator disposed between the positivecurrent collector of the first one of the plurality of bricks and thenegative current collector of the second one of the plurality of bricks.

In some implementations of the present technology, the at least oneconnector is a plurality of connectors, each one of the plurality ofconnectors being disposed in a corresponding one of the plurality ofchannels.

In some implementations of the present technology, wherein for eachbrick of the plurality of bricks, the plurality of battery cells arearranged in an alternating pattern, wherein the plurality of batterycells are arranged in a plurality of columns, and adjacent columns ofthe plurality of columns are vertically staggered from one another; andat least one of the plurality of battery cells is disposed between twoof the plurality of channels.

In some implementations of the present technology, the at least oneconnector is a metal fastener.

According to yet another aspect of the present technology, there isprovided a battery pack for a vehicle, comprising a first module groupcomprising at least one battery module; a second module group comprisingat least one other battery module; and a manually operable interrupterassembly selectively electrically connecting the first module group tothe second module group in series, the interrupter assembly beingadapted for opening and closing a circuit connecting the first andsecond module groups.

In some implementations of the present technology, a nominal voltage ofeach of the first and second module groups individually is less than ahigh voltage limit; and when the circuit is closed by the interrupterassembly, the first and second module groups are connected in series anda nominal voltage of the battery pack is greater than the high voltagelimit.

In some implementations of the present technology, the high voltagelimit is 60 Volts.

In some implementations of the present technology, when the circuit isclosed by the interrupter assembly, the nominal voltage of the batterypack is 96 Volts; and when the circuit is opened by the interrupterassembly, the nominal voltage of each of the first and second modulegroups is 48 Volts.

In some implementations of the present technology, each module groupcomprises at least two battery modules connected in series.

In some implementations of the present technology, the first modulegroup is mounted to a first location in the vehicle; the second modulegroup is mounted to a second location in the vehicle; and the firstlocation and the second location are spaced apart.

In some implementations of the present technology, each one of the atleast one battery module and the at least one other battery modulecomprises a plurality of bricks, each brick comprising a phase changematerial block; and a plurality of battery cells disposed at least inpart in the phase change material block.

Implementations of the present technology each have at least one of theabove-mentioned object and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presenttechnology that have resulted from attempting to attain theabove-mentioned object may not satisfy this object and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects and advantages ofimplementations of the present technology will become apparent from thefollowing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present technology, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 is a perspective view taken from a front, right side of a batterypack;

FIG. 2 is a perspective view taken from a front, right side of thebattery pack of FIG. 1 mounted in the frame of a vehicle;

FIG. 3 is a front elevation view of the battery pack of FIG. 1;

FIG. 4 is an exploded perspective view of a module of the battery packof FIG. 1;

FIG. 5 is an exploded perspective view of a brick of the module of FIG.4;

FIGS. 6a and 6b are perspective and front views, respectively, of a PCMblock of the brick of FIG. 4;

FIG. 7 is an exploded perspective view of portions of two adjacentbricks of the module of FIG. 4;

FIGS. 8 and 9 are perspective views taken from opposite sides ofportions of the module of FIG. 4;

FIGS. 10 and 11 are top plan and perspective views respectively ofportions of the module of FIG. 4; and

FIGS. 12 and 13 are top plan and perspective views respectively ofportions of the module of FIG. 4.

DETAILED DESCRIPTION

With reference to FIGS. 1 to 3, a battery pack 10 includes four batterymodules 12 a to 12 d arranged vertically, one atop the other. The fourmodules 12 a to 12 d of the pack 10 are mounted within the frame 14 of avehicle. The modules 12 a to 12 d are connected in series via cables 16a to 16 d, bus bars 18 a and 18 b, and switch assembly 20, hereinafterreferred to as an interrupter assembly 20. The cable 16 a connects thevehicle systems to a negative terminal 22 of the module 12 a, the busbar 18 a connects the positive terminal 24 of the module 12 a to thenegative terminal 22 of the module 12 b, the cable 16 b connects thepositive terminal 24 of the module 12 b to a first terminal 26 of theinterrupter assembly 20, the cable 16 c connects a second terminal 28 ofthe interrupter assembly 20 to the negative terminal 22 of the module 12c, the bus bar 18 b connects the positive terminal 24 of the module 12 cto the negative terminal 22 of the module 12 d, and the cable 16 dconnects the positive terminal 24 of the module 12 d to the vehiclesystems. The vehicle systems to which the cables 16 a and 16 d connectcan include, but are not limited to, a motor controller, a charger and aDC/DC converter.

The frame 14 of FIG. 2 is that of a three-wheeled, straddle seat roadvehicle, also called a roadster. It is contemplated that the vehiclecould be, inter alia, a two- or four-wheeled on-road vehicle, anoff-road vehicle such as an all-terrain vehicle, a side-by-side vehicleor a snowmobile, or a waterborne vessel such as a personal watercraft orboat. It is contemplated that the pack 10 could include more or lessmodules than the four modules 12 a to 12 d illustrated. As will bediscussed in more detail herein below, each module has a nominal voltageof 24V and the pack 10 has a nominal voltage of 96V. Providing twomodules 12 in series would provide a pack with a nominal voltage of 48V.It is also contemplated that the modules 12 a to 12 d could be arrangedother than vertically. For example, they could be arranged in two stacksof two modules 12 a to 12 d. It is contemplated that the modules couldbe mounted within a vehicle at different locations, i.e. not alladjacent one another.

The interrupter assembly 20 is electrically connected between themodules 12 b and 12 c, thereby enabling the user to manually open orclose the circuit between these two modules. During operation of thevehicle, the interrupter assembly 20 is closed, thereby completing thecircuit between the four modules 12 a to 12 d. When not in operation,such as during storage or maintenance, the interrupter assembly 20 canbe opened, thereby dividing the pack 10 into two halves, each with amaximum voltage of 48 volts. According to the SAE Surface VehicleStandard J1673 MAR2012, vehicle systems that contain a circuit operatingabove 50 volts (DC) are considered “high voltage” and surpass a highvoltage limit. Similar technical standards and/or regulations exist forother regions, such as the European Union's Directive 2006/95/EC whichpertains to circuits over 75 volts (DC) and the United Nations' UNECER100 which pertains to circuits over 60 volts (DC). As such, a vehiclecomprising the battery pack 10 can be rendered “low voltage” when not inuse. It will be appreciated that this can be advantageous for repairs,maintenance and the like.

FIG. 4 shows an exploded view of an exemplary module 12 (i.e. themodules 12 a, 12 b, 12 c, and 12 d have a similar construction). Forclarity, the module 12 has been inverted, that is to say its bottom sideis facing up. The module 12 and the components thereof will hereinafterbe shown in this orientation and spatial references such as “above” and“below” will, unless otherwise specified, be used in this frame ofreference.

The module 12 comprises a plurality of battery sub-modules 40,hereinafter referred to as bricks 40, a fuse 42, a current sensor 44 anda battery management system (BMS) 46, all housed within a housing 48.The housing 48 includes a housing body 50 which forms a cavity in whichthe bricks 40 are received. The housing 48 further comprises a lid 52which is secured to the housing body 50 by a plurality of bolts 54. Agasket 56 is positioned between the body 50 and the lid 52 in order toseal the cavity within the housing 48. A communication terminal 58 andthe negative and positive terminals 22 and 24 are provided on thehousing 48 so as to be accessible from outside the module 12. In oneimplementation, the body 50 and lid 52 are made of aluminum, although itis contemplated that other materials are possible.

Each brick 40 comprises a plurality of battery cells 60 surrounded by aPCM block 62 made of a PCM material, as will be described in furtherdetail herein below with reference to FIG. 5. During assembly, a layerof thermally conductive filler 64 is applied between the lid 52 and theplurality of bricks 40 so as to increase thermal conductiontherebetween. In the present implementation, the thermally conductivefiller 64 is thermal silicone (also called thermal grease) which isapplied during assembly in the form of a highly viscous liquid andhardens thereafter, filling any gaps between the bricks 40 and the lid52. It is contemplated that various types of thermal silicone, or otherhighly viscous thermally conductive filler materials, could be used inthe present application. The application of a suitable layer of thermalsilicone during assembly can help accommodate for any variations in thedimensions of the bricks 40 or the housing 48, thereby allowing forgreater tolerances while maximizing thermal conduction between thebricks 40 and the housing 48.

Another layer of thermal silicone 66 is applied between the bricks 40and the wall of the body 50 opposite the lid 52, which is similarlyintended to increase thermal conduction between the bricks 40 and thehousing 48. In use, heat generated within the cells 60 of each brick 40can be dissipated through the thermal silicone 64 and 66, and throughthe metallic housing 48 to the environment.

It is contemplated that an active heat exchange system, such as liquidcooling or forced air, could be added to the structure illustratedherein in order to further aid in cooling the cells 60. In particular,it is contemplated that the lid 52, or another part of the housing 48,could be provided with a liquid heat-exchanger in order to draw moreheat away from the module 12. Alternatively, fans could be providedproximate the lid 52, or another part of the housing 48, to forcecooling air across the module 12. The housing 48 could also be providedwith heat-exchange fins to encourage cooling. It is also contemplatedthat the lid 52, or other part of the housing 48, could be provided witha heating element for ensuring the cells 48 are warm enough whenoperating in a cold environment.

In order to ease assembly, the cavity formed within the body 50 has atapered shape and four foam wedges 68 a to 68 d are positioned betweenthe lateral walls of the body 50 and the bricks 40. The wedges 68 a to68 d can be formed, inter alia, from neoprene, plastic, polystyrene foamor the like, either alone or in combination. Additional layers ofthermal silicone or another thermally conductive filler could be used inplace of the wedges 68 a to 68 d.

FIG. 5 shows an exploded view of an exemplary brick 40. As mentionedabove, the bricks 40 each comprise a plurality of battery cells 60surrounded by the PCM block 62. More particularly, each brick 40comprises a total of 45 cells 60. The cells 60 are cylindrical in shapewith negative and positive terminals 70 and 71 at either extremity. Itis contemplated that the cells 60 are 18650 or 26650 cells, althoughother sizes could also be used. It is contemplated that the cells 60could be other than cylindrically shaped. It is also contemplated thatmore or less cells 60 could be provided per brick 40. In particular, itis contemplated that between 10 and 60 cells per brick 40 could beprovided.

The PCM block 62 comprises a plurality of slots 72, one for each of theplurality cells 60. Each slot 72 is sized to correspond to the length ofa corresponding cell 60. The thickness of the PCM block 62 equals thatof the cells 60 and each slot 72 extends through the entire thickness ofthe PCM block 62. When assembled, the negative and positive terminals 70and 71 of each cell 60 are flush with the faces of the PCM block 62 atthe extremities of their respective slots 62. It is also contemplatedthat the thickness of the PCM block 62 could be less than the length ofthe cells 60, such that their negative and positive terminals 70 and 71protrude beyond the PCM block 62, or that the thickness of the PCM block62 could be greater than the length of the cells 60.

The diameter of each slot 72 is sized to correspond with the diameter ofthe cells 60. In the implementation illustrated herein, the slots 72 aresized so as to ensure as much contact between the cells 60 along theirlateral sides as possible in order to maximize the transmission of heattherebetween, although other arrangements are possible. The cells 60 areoriented such that all of the negative terminals 70 are on one side ofthe PCM block 62 and all the positive terminals 71 are on the other.Referring to the frame of reference of FIG. 5, the negative terminals 70face rearward and the positive terminals 71 face forward.

Each brick 40 comprises first, second and third electrical insulators74, 76 and 78 which surround the PCM block 62. When assembled, theoutwardly-facing surfaces of the PCM block 62, i.e. those which are notfacing and/or in contact with the lateral sides of the cells 60, arecovered by a combination of the first, second and third electricalinsulators 74, 76 and 78.

The first electrical insulator 74 covers the rearward-facing side of thePCM block 62 and comprises openings 80 for each negative terminal 70.The first electrical insulator 74 also extends halfway across the top,bottom, left and right sides of the PCM block 62, from therearward-facing side towards the forward-facing side.

The second electrical insulator 76 is a mirror image of the firstelectrical insulator 74. It covers the forward-facing side of the PCMblock 62 and comprises openings 82 for each positive terminal 71. Thesecond electrical insulator 76 also extends halfway across the top,bottom, left and right sides of the PCM block 62, from theforward-facing side towards the rearward-facing side. When assembled,the first and second electrical insulators each cover half of theoutwardly-facing surfaces of the PCM block 62.

The third electrical insulator 78 extends around the top, bottom, leftand right faces of the PCM block 62. The third electrical insulator 78covers the seam between the first and second electrical insulators 74and 76. With the first, second and third electrical insulators inposition around the PCM block 62 and the cells 60, only the negative andpositive terminals 70 and 71 are uncovered.

Each brick 40 further comprises a negative current collector 84 which ispositioned adjacent and across the first electrical insulator 74. Thefirst electrical insulator 74 separates the negative current collector84 from the rearward-facing side of the PCM block 62, but the openings80 allow contact between the negative current collector 84 and thenegative terminals 70 of each cell 60. To ensure a conductiveconnection, the negative current collector 84 and the negative terminal70 of each cell 60 are ultrasonically welded to each other, although itis contemplated that other means of ensuring a conductive connectioncould be used, such as laser welding or friction welding.

Each brick 40 further comprises a positive current collector 88 which ispositioned adjacent and across the second electrical insulator 76. Thesecond electrical insulator 76 separates the positive current collector88 from the forward-facing side of the PCM block 62, but the openings 82allow contact between the positive current collector 88 and the positiveterminals 71 of each cell 60. To ensure a conductive connection, thepositive current collector 88 and the positive terminals 71 of each cellare friction welded to each other, although it is contemplated thatother means of ensuring a conductive connection could be used.

The negative and positive current collectors 84 and 88 are formed fromsheets of conductive material, such as nickel, copper or the like,either alone or in combination. The negative and positive currentcollectors 84 and 88 of the current implementation each comprise a sheetof nickel welded to a sheet of copper. Both sheets are 10 thousandths ofan inch (0.254 mm) thick, giving a total thickness of 20 thousandths ofan inch (0.508 mm). The negative current collector 84 comprises aplurality of contact portions 86, one for every opening 80. Whenassembled, each contact portion 86 is positioned opposite a respectiveopening and a respective negative terminal 70. The contact portions 86each have a forked shape with two branches that are friction welded tothe corresponding negative terminal 70 and a thinner base that connectsthe welded branches to the remainder of the negative current collector84.

The positive current collector 88 comprises a plurality of contactportions 90, one for every opening 82. When assembled, each contactportion 90 is positioned opposite a respective positive terminal 71. Thecontact portions 90 each comprise two tabs formed by H-shaped cut-outsin the positive current collector 88. The two tabs are each frictionwelded to the corresponding positive terminal 71.

Each brick 40 further comprises fourth and fifth electrical insulators92 and 94 which form its rearward-most and forward-most layersrespectively. The fourth and fifth electrical insulators 92 and 94 eachcover a substantial portion of the rearward-and forward-facing faces ofthe negative and positive current collectors 84 and 88, respectively.The first, second, third, fourth and fifth electrical insulators 74, 76,78, 92 and 94 of the present implementation are formed from sheets ofelectrical insulation paper, such as ThermaVolt™ manufactured by 3M™,which is held in place by an adhesive backing.

The cells 60 are arranged within the PCM block 62 in an alternatingpattern that forms a plurality of channels 96 across the top of the PCMblock 62. The first, second, third, fourth and fifth electricalinsulators 74, 76, 78, 92 and 94 comprise corresponding shapes alongtheir upper sides/edges. The present implementation of the PCM block 62and the 45 slots 72 that receive the 45 cells 60 are shown in moredetail in FIGS. 6a and 6b . The slots 72 are aligned in nine columns 98a to 98 i of five slots 72 each, i.e. the longitudinal axis 100 a of agiven slot 72 will be aligned with the longitudinal axes 100 b and 100 cof the slots 72 above and below it. Each column 98 a to 98 i is offsetvertically from the adjacent column(s) to the left and/or to the rightof it, i.e. the longitudinal axis 100 a of the slot 72 will not bealigned with longitudinal axes 100 e to 100 h of the slots 72 to theleft and to the right of it. As such, a given cell 60 will have anothercell 60 immediately above and/or below it at the same horizontalposition across the width of the PCM block 62 (thereby forming thecolumns 98 a to 98 i), but the cells 60 to the left and/or right of itwill not be at the same vertical position across the height of the PCMblock 62. In the present implementation, the longitudinal axes 100 e to100 h are vertically offset from the longitudinal axis 100 a (eitherupwards or downwards) by half the distance between the longitudinal axes100 a and the longitudinal axes 100 b and 100 c above and below it. Thisalternating pattern permits a tighter packing of the cells 60 within thePCM block 62 and a reduction in the width of the PCM block 62.Staggering the cells 60 in this way also allows the formation ofchannels 96 a to 96 e along the top side of the PCM block 62 beside andbetween the second, fourth, sixth and eighth columns 98 b, 98 d, 98 fand 98 h.

It is contemplated that channels similar to those shown in FIGS. 6a and6b could be provided along the bottom side of the PCM block 62 either inaddition to or in place of the channels 96 a to 96 e. While the presentimplementation comprises an alternating pattern of columns, it iscontemplated that the cells 60 and slots 72 could similarly be arrangedin an alternating pattern of rows that form channels along the leftand/or right sides of the PCM block 62.

The modules 12 shown in the present implementation each comprise sevenbricks 40, although it is contemplated that more or less bricks 40 couldbe provided per module 12. It is contemplated that between six and 20bricks 40 could be provided. The cells 60 of the brick 40 are connectedin parallel via the negative and positive current collectors 84 and 88which connect the negative and positive terminals 70 and 71,respectively, of each cell. The seven bricks 40 of each module 12 areconnected in series, that is to say the negative current collector 84 ofone brick 40 is connected to the positive current collector 88 of anadjacent brick 40 such that the voltage of the module 12 is the sum ofthe voltages of the bricks 40 therein. As discussed above, the fourmodules 12 are also connected in series.

With reference to FIG. 7, two exemplary bricks 40 a and 40 b are shownin a partially exploded state to illustrate the connection therebetween.For clarity, the elements of the left brick 40 a (with respect to theframe of reference of FIG. 7) are labeled with the suffix “a” while,similarly, the elements of the adjacent right brick 40 b are labeledwith the suffix “b”. When assembled, the fifth electrical insulator 94 aof the left brick 40 a is adjacent the fourth electrical insulator 92 bof the right brick 40 b. The presence of the electrical insulators 94 aand 92 b separate the negative and positive current collectors 88 a and84 b, except along their upper edges where they will be connected asdescribed below. The electrical insulators 94 a and 92 b prevent thecontact portions 90 a of the positive current collector 88 a from cominginto contact with the contact portions 86 b of the negative currentcollector 84 b.

The positive and negative current collectors 88 a and 84 b of theadjacent bricks 40 a and 40 b are electrically connected by a pluralityof connectors 104 which are embodied herein by bolts 106, nuts 108 andwashers 110. Each bolt 106 passes through a hole 112 a in the positivecurrent collector 88 a and a corresponding hole 114 b in the negativecurrent collector 84 b. The washers 110 sandwich the portion of thenegative and positive current collectors 88 a and 84 b around the holes112 a and 114 b, ensuring a contact therebetween. In addition, the bolts106, nuts 108 and washers 110 are metallic and can conduct currentbetween the bricks 40 a and 40 b. The holes 112 a and 114 b are locatedalong the top edge of the positive and negative current collectors 88 aand 84 b, respectively, such that the bolts 106, the nuts 108 and thewashers 110 are located in the channels 96. In the presentimplementation, there are four pairs of holes 112 a and 114 b, eachwithin a channel 96. It will be appreciated that various alternativeways of connecting negative and positive current collectors 88 a and 84b, such as welding, rivets, clamps, clips and the like. It is alsocontemplated that adjacent current collectors 88 a and 84 b could beformed from a single conductive sheet folded in half with one or both ofthe electrical insulators 94 a and 92 b therebetween.

FIGS. 8 and 9 show seven bricks 40 a to 40 g connected in series betweenthe positive and negative terminals 24 and 22. The charge path(indicated in with arrows and representing a positive current directionas seen by the BMS 46) begins at the positive terminal 24 which hisconnected to the first brick 40 a via a first bus bar 116. The first busbar 116 is connected to the positive current collector 88 of the firstbrick 40 a via connectors 104 which engage the holes 112 of the firstbrick 40 a and a corresponding set of holes (not shown) in the bus bar116 in a manner similar to that described above. The negative currentcollector 84 of the first brick 40 a is connected to the positivecurrent collector 88 of the second brick 40 b, the negative currentcollector 84 of the second brick 40 b is connected to the positivecurrent collector 88 of the third brick 40 c, and the negative currentcollector 84 of the third brick 40 c is connected to a second bus bar118. These connections are all made via connectors 104 which engageholes 112 and/or 114.

The charge path continues through the second bus bar 118 to the positivecurrent collector 88 of the fourth brick 40 d. The negative currentcollector 84 of the fourth brick 40 d is connected to the positivecurrent collector 88 of the fifth brick 40 e, the negative currentcollector 84 of the fifth brick 40 e is connected to the positivecurrent collector 88 of the sixth brick 40 f, the negative currentcollector 84 of the sixth brick 40 f is connected to the positivecurrent collector 88 of the seventh brick 40 g, and the negative currentcollector 84 of the seventh brick 40 g is connected to a third bus bar120. Again, these connections are all made via connectors 104 whichengage holes 112 and/or 114.

The charge path continues from the third bus bar 120 to the fuse 42, thecurrent sensor 44 and ends at the negative terminal 22. The internalcomponents of the negative and positive terminals 22 and 24, the bus bar116, the current sensor 44, the fuse 42 and the BMS 46 (not shown inFIGS. 8 and 9) occupy a space roughly the size of a brick 40. Thepresent architecture of seven bricks 40 and the accompanying electricaland electronic components form a substantially U-shaped package withinthe module 12. It is contemplated that the bricks 40 could be arrangedand connected in other formations, such as in a single line, in an Sshape or and M shape.

The BMS 46 of each module 12 monitors and logs the temperature andvoltage of each brick 40, and the current through the module 12 (via thesensor 44) to ensure these parameters stay within their operationallimits. The BMS 46 can register fault and/or error codes when thoselimits are exceeded. The BMS 46 also calculates the state of charge andstate of health of the module 12 and bricks 40. Each BMS 46 outputs thisinformation via the communication terminal 58 to the vehicle's CAN-busnetwork to a vehicle control module (not shown) that also communicateswith the vehicle's motor controller(s).

The cells 60 are lithium-ion rechargeable cells. More particularly, theyare lithium-nickel-manganese-cobalt cells (NMC), although other types ofcells are contemplated. For example, it is contemplated that the cells60 could be lithium-nickel-cobalt-aluminum (NCA),lithium-manganese-spinel (LMO), lithium-titanate (LTO),lithium-iron-phosphate (LFP) cells or lithium sulfur (Li—S). The nominalvoltage of each NMC cell 60 is 3.65V. Accordingly, the voltage of eachbrick 40 is 3.65V, the voltage of each module 12 comprising seven bricks40 is 25.55V and the voltage of each pack 10 comprising four modules 12is 102.2V. Such a module is said to have a nominal voltage of 24V andsuch a pack 10 is considered to have a nominal voltage of 96V. In thepresent implementation, each module 12 has 2.5 kwh at 24V resulting in10 kwh at 96V with 30 kW continuous power and 55 kW peak power for thepack 10. It will be appreciated that NCA cells have an equivalentvoltage to NMC cells and as such the resultant voltages of the bricks40, modules 12 and packs 10 comprising NCA cells would be equivalent tothose of the NMC cells 60. It is contemplated that a 120V pack 10comprising Li—S cells having a nominal voltage of 2.2V could also beprovided.

The PCM block 62 acts as a heat sink during discharge of the cells 60.Preventing the cells 60 from getting too hot during discharge isimportant to both prevent thermal runaway and protect the cells fromdamage which could reduce their performance and lifespan, as ismaintaining an even temperature across all the cells 60 of a given brick40. It is contemplated that the PCM block 62 could be formed from a waxand graphite matrix PCM material, such as the Phase Change Composite(PCC™) material manufactured by Allcell. During discharge, as the cells60 heat up, the PCM block 62 thermally conducts that heat to spread itout evenly across the brick 40. As the temperature of the brick 40, orany parts thereof, approaches the melting point of the PCM block 62(T_(melt)), heat energy begins to be absorbed by the melting (i.e. phasechange) process. The proportion of the PCM block 62 that has melted at agiven moment is referred to as the liquid fraction. When the liquidfraction has reached 100%, every part of the brick 40 will have reachedT_(melt) and the PCM material can absorb no further heat. Once dischargehas stopped, the PCM block 62 will release the heat absorbed duringdischarge to the surrounding environment and the liquid fraction willeventually return to 0%.

Different PCM materials will have different T_(melt), for example PCMmaterials are available that have 43° C., 48° C. or 55° C. The PCM block62 is selected so that the T_(melt) is below a maximum desired operatingtemperature during discharge (T_(max-discharge)) in order to helpprevent thermal runaway and damage to the cells 60 and above the maximumambient temperature of operation of the battery pack 10. For example, inthe present implementation the T_(max-discharge) of the cells 60 is 60°C. The PCM block 62 is therefore selected to have a T_(melt) lower than60° C. It is common to select PCM material that has the highest T_(melt)lower than the T_(max-discharge).

However, the cells 60 also have a maximum temperature at which they canbe charged (T_(max-charge)). T_(max-charge) is typically less thanT_(max-discharge). For example, the cells 60 of the presentimplementation have a T_(max-charge) of 45° C. Cells 60 that havereached a temperature above T_(max-charge) during operation (i.e.discharge) cannot be charged until the pack 10 has cooled to belowT_(max-charge). A conventional battery pack with cells having aT_(max-discharge) of 60° C. and a PCM material having a T_(melt) of 55°C. that undergoes heavy usage and discharge of the cells thatnecessitates absorption by the PCM material will not be able to berecharged immediately after usage since the battery pack must cool to45° C. (T_(max-charge)). The PCM block 62 of the present implementationtherefore comprises a PCM material with a T_(melt) lower than theT_(max-charge) in order to ensure that the cells 60 will be ready to berecharged immediately after they are discharged. This can be especiallyadvantageous in implementations where quick recharging is desirable.

As mentioned above, the BMS 46 monitors the voltage of each brick 40.With reference to FIGS. 10 and 11, a module 12 is shown with a voltagemonitoring assembly 122 which links the BMS 46 to each of the bricks 40a to 40 g. The voltage monitoring assembly 112 comprises a wire harness124 comprising eight wires 126 a to 126 h which connect the BMS 46 topoints before and after each brick 40 a to 40 g. A first extremity ofthe first wire 126 a is connected to the positive current collector 88of the first brick 40 a. A first extremity of the second wire 126 b isconnected to the negative current collector 84 of the first brick 40 aand the positive current collector 88 of the second brick 40 b. A firstextremity of the third wire 126 c is connected to the negative currentcollector 84 of the second brick 40 b and the positive current collector88 of the third brick 40 c. A first extremity of the fourth wire 126 dis connected to the positive current collector 88 of the fourth brick 40d and the second bus bar 118. A first extremity of the fifth wire 126 eis connected to the negative current collector 84 of the fourth brick 40d and the positive current collector 88 of the fifth brick 40 e. A firstextremity of the sixth wire 126 f is connected to the negative currentcollector 84 of the fifth brick 40 e and the positive current collector88 of the sixth brick 40 f A first extremity of the seventh wire 126 gis connected to the negative current collector 84 of the sixth brick 40f and the positive current collector 88 of the seventh brick 40 g. Afirst extremity of the eighth wire 126 h is connected to the negativecurrent collector 84 of the seventh brick 40 g and the third bus bar120.

The first extremities of each wire 126 a to 126 h are electricallyconnected to respective positive and negative current collectors 88 and84 via connectors 104 in the manner described above. The harness 124extends along a central channel 128 formed along the center of themodule by the innermost channels 96 of the bricks 40 a to 40 g. Theconnections between the first extremities of the wires 126 a to 126 hand the bricks 40 a to 40 g are made within the central channel 128.

Each wire 126 a to 126 h comprises a second extremity opposite itsrespective first extremity that is connected to a voltage monitoringassembly connector 130 that plugs into the BMS 46. The BMS 46 istherefore provided with the voltage before and after each brick 46 a to46 g, thereby enabling monitoring of the voltage of each brick 46 a to46 g.

The harness 124 further comprises a first power wire 132 a having afirst extremity connected to a BMS power connector 134 and a secondextremity connected to the positive current collector 88 of the firstbrick 40 a. The voltage monitoring assembly 122 further comprises asecond power wire 132 b having a first extremity connected to the BMSpower connector 134 and a second extremity connected to the negativecurrent collector 84 of the seventh brick 40 g and the third bus bar120. The first and second power wires 132 a and 132 b provide the 24V ofthe module 12 to power the BMS 46.

As mentioned above, the BMS 46 also monitors the temperature of eachbrick 40 a to 40 g. With reference to FIGS. 12 and 13, a module 12 isshown with a temperature monitoring assembly 136. The assembly 136comprises a wire harness 138 comprising eight wires 140 a to 140 h whichconnect the BMS 46 to points across the module 12. The first extremityof each wire 140 a to 140 h is connected to a thermistor 142. The secondextremity of each wire 140 a to 140 h is connected to a temperaturemonitoring assembly connector 144 that plugs into the BMS 46.

The thermistor 142 of the first wire 140 a is connected, via a connector104, to the first bus bar 116. The thermistors of the wires 140 b to 140h are each in contact with a respective one of the PCM blocks 62 of thebricks 40 a to 40 g. Specifically, these thermistors 142 are passedthrough an opening in respective electrical insulators 74, 76 and/or 78so as to contact respective PCM blocks 62 directly. The thermistors 142can be glued or otherwise fixed in position. Like the wire harness 124of the voltage monitoring assembly 122, the wires 140 a to 140 h of thewire harness 138 extend from the connector 144 through the channel 128formed by the innermost channels 96 of the bricks 40 a to 40 g.

Modifications and improvements to the above-described implementations ofthe present technology may become apparent to those skilled in the art.The foregoing description is intended to be exemplary rather thanlimiting.

What is claimed is:
 1. A battery pack for a vehicle, comprising: a firstmodule group comprising at least one battery module; a second modulegroup comprising at least one other battery module; and a manuallyoperable interrupter assembly selectively electrically connecting thefirst module group to the second module group in series, the interrupterassembly being adapted for opening and closing a circuit connecting thefirst and second module groups.
 2. The battery pack of claim 1, wherein:a nominal voltage of each of the first and second module groupsindividually is less than a high voltage limit; and when the circuit isclosed by the interrupter assembly, the first and second module groupsare connected in series and a nominal voltage of the battery pack isgreater than the high voltage limit.
 3. The battery pack of claim 1,wherein the high voltage limit is 60 Volts.
 4. The battery pack of claim2, wherein: when the circuit is closed by the interrupter assembly, thenominal voltage of the battery pack is 96 Volts; and when the circuit isopened by the interrupter assembly, the nominal voltage of each of thefirst and second module groups is 48 Volts.
 5. The battery pack of claim3, wherein: when the circuit is closed by the interrupter assembly, thenominal voltage of the battery pack is 96 Volts; and when the circuit isopened by the interrupter assembly, the nominal voltage of each of thefirst and second module groups is 48 Volts.
 6. The battery pack of claim1, wherein: each module group comprises at least two battery modulesconnected in series.
 7. The battery pack of claim 1, wherein: the firstmodule group is mounted to a first location in the vehicle; the secondmodule group is mounted to a second location in the vehicle; and thefirst location and the second location are spaced apart.
 8. The batterypack of claim 1, wherein each one of the at least one battery module andthe at least one other battery module comprises: a plurality of bricks,each brick comprising: a phase change material block; and a plurality ofbattery cells disposed at least in part in the phase change materialblock.
 9. The battery pack of claim 2, wherein each one of the at leastone battery module and the at least one other battery module comprises:a plurality of bricks, each brick comprising: a phase change materialblock; and a plurality of battery cells disposed at least in part in thephase change material block.